Packing cup retainer



March 9, 1943. s, c'HN L'L 2,313,271

PACKING CUP RETAINERS Filed Dec. 16, 1939 FIG}. 1

INVENTOR VE SCHNELL BY g5 Q the surfaces it contacts that the cup in either direction.

Patented Mar. 9, 1943 I uurr zo I STATES PATENT Price Steve Schnell. Overland,

Electric Corporation. St.

tion of Delaware PACKINGOUPRET Mo., to Wagner Louis, Mo., a corpora- Applicatlon December 16, 1939, Serial No. 309,5'71

1 Claim.

My invention relates to packing cups for pistons and more particularly to means for retaining the cup on the pisto One of the objects of my-invention is to provide an improved means for retaining a packing cup in proper position on the head of a piston.

Another object of my invention is to provide a readily attachable and detachable retaining means for an annular type of piston packing cup which will at all times hold the cup in engage-'- ment with the head of the piston and also cause the cup to have such pressure engagement with fluid cannot pass Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing in which Figure 1 is a cross-sectional view of a cyl-- inder and piston having associated therewith a packing cup and retainer embodying my invention; and Figures 2 and 3 are views showing the packing cup and retainer as detached from the piston.

Referring to the drawing in detail, numeral I indicates a cylinder having associated therewith a piston 2 which can be either actuated by the groove 1 of the cup. The inner portion of the body carries axially extending fingers I4 and. the ends are adapted to engage shoulder II when the retainer is in operative position. The length of these fingers is such in relation to the cup and other parts that when engaging the shoulder they willcause the body portion lt to apply an axial compressing force on the cup at the groove I and in a direction toward the face of the plston. This force will insure that the cup will at all times be held in engagement with the face of the piston during relative movement between the piston and cylinder. Also this force will cause thecup, due to its yieldability, to flow" in such directions as to engage thecylinder wall and; the surface of the projection withwonsiderablev pressure which will be suflicient to seal fluid in the chamber ahead of the piston or prevent it from entering the chamber by passing the piston.

the piston rod 3 if it is desired to produce fluid an annular groove 1 which forms an outer lip' portion 8 engaging the cylinderwall and an inner lip portion 9 engaging the surface of the projection 5.. Y

The forward end of the piston projection has an annular shoulder it which is at a slightly greater distance from the face of the piston than the axial thickness of the cup. On the shoulder It there is also provided a second annular shoulder ll.

In order to maintain the cup in proper position on the projection and insurethat the cup will have pressure engagement with the cylinder wall. the piston face and the surface of the projection there is provided my pecial retainer 12. The

body ll of the retainer is of annular form and of ed on the The retainer and cup can be very easily mountpiston as the cup need only be mounted on the projection by stretching it sufllciently to get it over the shoulders and then the retainer pressed into position. The fingers H are resilient and will snap" to position behind the shoulder II. To remove he retainer, the lingers-need only be sprung out from behind the shoulder. By the use of the retainer the cup will be prevented from having any relative movement withrespect to the piston. thus insuring that the sharp inner sealing corner on. the innerlip I will not be damaged by butting against the shoulder It as would be the case if the retainer werevnot used. .Also the fingers I! hold the lip 9 against the surface of the projection and assist in the sealing at this point. It is also to be noted that the outer portion of the U-shaped body of the retainer is so shaped in relation to the adjacent surface of groove 1 of the cup that a portion of the inner surface of lip 8 will be exposed to fluid pressure whereby said pressure can apply a force assisting in maintaining the lip in engagement with the cylinder wall. It the cup should swell because of the fluid used. the retainer will only cause the cup to engage the surfaces it contacts with a greater pressure, thus increasing the sealing action.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles of my invention do not intend that its scop be.

limited except as set forth by the appended claim U-shaped radial cross section so as to fit into. il- 8 es d y invention; a I

claim as new and desire to secure by Letters Patent of the United States is:

In fluid pressure apparatus, a cylinder, a piston provided with a projection having a shoulder spaced from the piston face, an annular sealing cup of yieldable material positioned on the projection and having an annular groove in its forward face forming inner and outer lips for engagement with the cylinder wall and the surface of the projection, respectively. and a retainer for preventing the cup from having relativ movement with respect to the piston and the projectlon, said retainer comprising a member COD! structed of a single piece of thin metal and having an annular portion of U-shaped radial crosssection for engaging the base of the groove by its outer curved surface and integral axially extending fingers overlying and engaging the surface of the inner lip to firmly hold it in contact with the surface of the projection and having their ends engaging the shoulder, said fingers being laterally fiexible with respect to the annular portion to permit their being passed over the shoulder and to a position behind the shoulder when the retainer is placed in operative position and to facilitate their disengagement from the shoulder when the retainer isto be removed and said fingers also being of such length that when positioned behind the shoulderthey will cause the annular portion to apply an axial pressure to the cup by means of the annular portion of -U -shaped radial cross-section to thereby force the cup into pressure engagement with the piston face, the projection and the cylinderwall without cutting the material thereof.

' STEVE SCI-INELL. 

